Incentive spirometer

ABSTRACT

The device has a disposable unit and a re-usable unit. The disposable unit comprises a piston and vertical cylinder, a flexible tube connected with the top of the cylinder and a mouthpiece on the tube. The tube enables a patient to inhale air from the cylinder causing the piston to rise. A controlled leakage is provided between the piston and cylinder making it necessary for the patient to continue inhaling through the tube in order to hold the piston at the top of its upward stroke. The re-usable unit is an indicator unit containing a battery, a signal light and a switch which is held closed as long as the piston remains at the top of its stroke. The light provides incentive for the patient to continue inhalation as long as possible. A counter in the indicator unit records the number of inhalations made in a day or other given period of time.

United States Patent [191 Cooper INCENTIVE SPIROMETER [75] Inventor: Robert P. Cooper, La Puente, Calif. [73]v Assignee: American Hospital Supply Corporation, Evanston, Ill.

[22] Filed: June 10, 1971 21 Appl. No.: 151,756

[52] Us. Cl. l28/2.08, 272/57 R [51] Int. Cl A61b 5/08 [58] Field 01 Search l28/2.08, 2.07, 2 R; 272/57 R; 73/379 R [56] Reterences Cited UNITED STATES PATENTS 3,635,214 1/1972 Rand et al. 1 28/2.08 3,467,078 9/1969 Bird et al l28/2.08 761,369 5/1904 Francis 128/2.08 737,296 8/1903 Taylor 128/2.08 331,829 12/1885 Shepard.... 128/2.08 51,002 11/1865 Barnes 128/2.08

FOREIGN PATENTS OR APPLICATIONS 1,124,631 3/1962 Germany 128/2.08 OTHER PUBLICATIONS 1451 Aug. 28, 1973 plication to Post Operative Care, Surgical Forum, 1970, pp. 222-224.

Doctors Test Yawn Box, Boston Evening Globe, Oct. 14, 1970.

Primary Examiner-Kyle L. Howell AttomeyLee R. Schermerhorn ABSTRACT The device has a disposable unit and a re-usable unit. The disposable unit comprises a piston and vertical cylinder, a flexible tube connected with the top of the cylinder and a mouthpiece on the tube. The tube enables a patient to inhale air from the cylinder causing the piston to rise. A controlled leakage is provided between the piston and cylinder making it necessary for the patient to continue inhaling through the tube in order to hold the piston at the top of its upward stroke. The reusable unit is an indicator unit containing a battery, a signal light and a switch which is held closed as long as the piston remains at the top of its stroke. The light provides incentive for the patient to continue inhalation as long as possible. A counter in the indicator unit records the number of inhalations made in a day or other given period of time.

Bartlett, R. H. et al., Physiology of Yawning & lts Ap- 12 Claims, 5 Drawing Figures 6|' 1 12 B\ 70 55 5s 71 6 7 I I I I l 32\ L l, M0 +0 n 1 I s v I g PATENTED M19 28 I873 I/VVEIVTUR ROBERT P COOPER fliiorney LLLL I BACKGROUND OF THE INVENTION This invention relates to an incentive spirometer which is arranged to provide assurance both to a patient and to his physician that the patient is performing a prescribed respiratory maneuver.

Shallow breathing, decreased lung volumes and increased transpulmonary shunting as high as twenty percent of the cardiac output are consistent findings in most patients following major operations. These alterations in pulmonary function usually return to normal without becoming clinically evident but may progress to obvious respiratory insufficiency with decreased compliance, increased work of breathing, marked shunting, retention of secretions, gross consolidation and pneumonitis. The causes of these phenomena are uncertain but monotonous tidal ventilation leading to alveolar closure has been shown to have this effect..

Various methods involving forced expiration have heretofore been proposed for preventing such pulmonary complications but this approach has proved unsatisfactory and ineffective. These methods do not require maximum inflation of the lungs, and are painful to the patient because the abdominal muscles are predominantly expiratory muscles. Also, induced deep breathing by other methods such as re-breathing', CO breathing, and merely asking the patients to breathe deeply, do not result in inhalation to total lung capacity. i Likewise, inflating the lungs by positive pressure has proved to be unsatisfactory. Unless the patients are carefully instructed in the use of positive pressure breathing devices, they tend to resist the inspiratory flow before-a large volume is reached. Many patients swallow involuntarily during the inspiratory phase and may suffer acute gastric dilatation. There are also other objections to positive oressure breathing.

A more effective method, and apparatus designated as an incentive spirometer, were reported in Surgical Forum 1970, pages 222 to 224, by Robert I-LBartlett,

M.D., Paul Krop, M.D'., E. Lawrence Hanson, MD; and. Francis D. Moore, M.D., F.A.'C.S., in an article titled: Physiology of Yawning and Its Application to Post. Operative Care." Another publication of this method and apparatus will be found in anarticle in the Boston Evening Globe, October 14, tors- Test Yawn Box.

Objects of the present invention are, therefore, to provide an improved incentive spirometer, to provide an incentive'spirometer having a=disposable airway unit and a. re-usable indicator unit, and-toprovide an" incentive spirometer of: improvedand' simplified construction whichis economicaltomanufacture and convenient for the patient to use'with'a minimum of instructionandisupervision.

' SUMMARY OF THE lNVEhFFIO N In the present constructionthe device is made with a disposable airway unit and are-usable indicator unit.

1 The airway unit comprises-averticalcylinder containing a piston, a' flexible inhalation tube and a mouth-.

piece. The indicator unitis detachably mounted on the upper endof'the*cylinder-.-As the piston :rises during inhalationthrough the mouthpiece, tlie'pis'ton engages an adjustable volume indicatorf rod iri the indicator unit which is capable of limitedivertical movement. Upward movement of the indicator rod when it is engaged by the piston actuates a counter and tums on a signal light in the indicator unit.

The patient is instructed to keep the light on as long' as possible in each inhalation. In order to keep the light on, the patient must maintain a flow of air into his lungs at a rate equal to a controlled leakage provided between the cylinder and piston. This assures filling of the patients lungs to maximum capacity in each inhalation. If the patient closes his glottis, or when total lung capacity is reached and an inspiratory flow can no longer be maintained, the piston falls, the switch opens and the light goes off.

The invention will be better understood and additional objects and advantages will become apparent from the following description of the preferred embodiment illustrated on the accompanying drawing. Various changes may be made in the details of construction and arrangement of parts and certain features may be used without others. All such modifications within the scope of the appended claims are included in the invention.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION ,OF THE PREFERRED EMBODIMENT The device has a disposable airway unit A and a reusable indicator unit B. Airway unit A comprises a ver- FIG. 1, with parts I tical cylinder 10, piston 11, flexible inhalation tube 12 and mouthpiece 13 as shown in FIGS. 1 and 2. In use, the indicator unit B is mounted on top of cylinder 10 and the whole device is adapted to rest on the open lower end of the cylinder. 7 a

The lower end of the cylinder wall is cut away at 15 to provide a free flow of air into and out of the lower end of the cylinder. Rivets 16' form stops to retain piston 11 in the cylinder. Tube 12 is connected with an.

upstanding nipple 17 in the top wall 20 of the cylinder. Cylinder l0 and piston vll are preferably made of an inexpensive material such as plastic or cardboard tube sections with sheet metal end walls. Piston 11 has a loose fit in cylinder 10 and is dimensioned to provide a controlled leakage through leakage space 18 of 50 to cubic centimeters per second of air at a pressure differential of 2 millimeters of mercury.

For convenient detachable connection of indicator unit 8, the top wall 20 of the cylinder l0'is provided with an upstanding boss or hub 21 having a bore '22 communicating with the upper end of the cylinder. A pair of vertical slots 23 intersect an annular groove 24' to form a bayonet joint type of connector- In the indicator unit B, a housing 30 contains a mounting plate 31 secured to a connector pin ring 32,

- A pair of radial pins 33 projects into a central opening 34 in ring32. Opening 34 receives the hub 21' as the pins'33 are moved downward through slots 23 into annular groove 24. Then, by rotating the indicatoru'nit' through a fractional turn on the hub 21, the pins 33 will rotate in groove 24 to lock the units A and B together.

The bayonet joint connection just described is made secure by three spring feet 40 on indicator unit B which bear against the top wall 20 of the cylinder 10. Each foot 40 is slidably mounted in a bore 41 in mounting plate 31. The foot is retained in the bore by a stop washer 42 disposed in a counterbore 43. A screw 44 in the foot secures washer 42 to the upper end of the foot. The foot is pressed downward by a leaf spring 45 which is secured to mounting plate 31 by screws 46. Thus, the three feet 40 serve to stabilize indicator unit B on the hub 21 and press the inner ends of pins 33 against the top wall of groove 24 to prevent looseness in the bayonet joint connection.

Ring 32 is secured to mounting plate 31 by threaded lower ends on a pair of vertical posts 50 and 51. Screws 52 in the upper ends of these posts secure a top cover plate 53 on the housing 30. Posts 50 and 51 also form guides for a vertically movable rod guide column 55 which extends through an opening 54 in cover plate 53. Guide column 55 has an enlarged base portion 56 containing a vertical bore 57 which is slidable on post 50 and a notch 58 which is slidable on post 51.

Rod guide column 55 has a bore 59 slidably receiving a cylindrical volume indicating rod 60. Rod 60 may be raised and lowered in guide column 55 and secured in adjusted position with reference to a volume scale 64 by a clamp nut 61. Clamp nut 61 is mounted on a threaded upper end portion 62 of rod guide column 55 which is slightly eccentric to the bore 59. Rotation of nut 61 through .a fractional turn causes an edge of an opening 63 in the top of the nut to bind and clamp the rod 60.

Rod 60 extends downward through bore 22 in hub 21 into the upper end of cylinder 10 as shown in FIG. 2. Any leakage of air between rod 60 and the wall of bore 22 is taken into consideration in establishing the desired total leakage of air into the cylinder under inhalation pressures. By means of the clamp nut 61, the rod may be adjusted up and down as indicated by the arrow 65 so that it will be engaged by piston 11 at a predetermined point in the upward movement of the piston. When the upward moving piston thus raises the rod 60 and rod guide column 55, a pin 66 on the latter lifts a counter arm 67 to actuate the counter 70 which is visible through a window in cover plate 53. The counter is equipped with a reset knob 71.

Further upward movement of rod guide column 55 brings'its base portion 56 into engagement with a leaf switch 75, causing the switch to close an electric circuit. Switch 75 stops the upward movement of guide column 55, rod 60 and piston 11. Switch 75 is connected in a circuit with a pair of batteries 76 and a signal light 77 to energize the light. As long as rod guide column 55 is held up against switch 75 by the piston 11, the light will remain on; as soon as rod guide column 55 leaves contact-with switch 75, the light is turned off.

In operation, the rod 60 is adjusted by nut 61 in accordance with the patients lung capacity. Starting with small inspiratory volumes of about 500 cc., the rod is raised during the course of repeated trials according to the patients ability. Preferably, the inspiratory volume which will turn on the light is set 250 to 500 cc. below the patients best effort so that the lightwill remain on to seconds during each inhalation. This inspiratory volume equals about one-half the patients maximum lung capacity.

The patient is instructed to continue each inhalation I as long as possible at a rate sufficient to keep the light from turning off. The continued glowing of the light provides a reward for large volume sustained inspiration. As soon as the rate of inhalation falls below the spirometer leakage rate, the rod 60 and piston 11 descend by gravity and turn the light off. Regular use of the device for 5 days after operation reduces the incidence of post-operative pulmonary complications.

in comparison to prior methods of preventing pulmonary complications, use of the present device does not decrease cardiac output, the patient does not swallow air and, unlike positive pressure breathing, the maximum inspired volume is assured. The maximum inspired volume is total lung capacity with all available alveoli open.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. An incentive spirometer comprising an airway unit and an indicator unit; said airway unit comprising a ver tical cylinder having a top end wall and an open bottom end, a loosely fitting piston in said cylinder having predetermined air leakage rate, and an inhalation tube connected with the upper end of said cylinder; said indicator unit comprising an electrical power supply means, a signal light, a switch in circuit with said light for turning said light on and off, and a switch actuating member for said switch; and quick detachable means connecting said two units together with said switch actuating member arranged to be lifted by upward movement of said piston to turn on said light when said piston has been raised to a predetermined position in said cylinder by inhalation of a person through said tube.

2. A spirometer. as defined in claim 1 including a counter in said indicator unit mounted for actuation by said switch actuating member.

3. A spirometer as defined in claim 1 wherein said switch actuating member extends into said cylinder through said quick detachable connecting means.

4. A spirometer as defined in claim 1, said quick detachable connecting means comprising complementary interengaging parts on said top end wall of said cylinder and the bottom of said indicator unit for mounting said indicator unit on said top end wall with said switch actuating member extending through an opening in said top end wall for engagement by said piston.

5. A spirometer as defined in claim 1, said switch actuating member forming a stop to limit said upward movement of said piston.

6. A spirometer as defined in claim 5, said switch actuating member comprising a rod mounted for engagement with said piston, a rod guide column mounted in said indicator unit and forming means having limited movement to actuate said switch, and means securing said rod in adjusted position in said rod guide column.

7. An incentive spirometer comprising a vertical cylinder having a top end wall and an open lower end, an inhalation tube connected with the upper end of said cylinder, a loosely fitting piston in said cylinder having a predetermined air leakage rate, an indicator unit mounted on said top end wall of said cylinder and containing a counter and a signal light, a switch in said indicator unit for turning said light on and off, electrical power supply means for said signal light, a rod guide column mounted for vertical movement in said indicator unit and forming means to actuate said counter and switch, and a vertical volume indicating rod adjustably mounted in said rod guide column, the lower end of said rod extending into said cylinder for engagement by the top of said piston.

8. A spirometer as defined in claim 7 including quick detachable means for connecting said indicator unit to said top end wall.

9. A spirometer as defined in claim 8, said quick detachable means comprising a bayonet-type connector having a grooved hub on said top end wall of said cylinder and a ring on the bottom of said indicator unit arranged to lock on said hub, said hub having a bore slidably receiving said rod.

10. A spirometer as defined in claim 9 including spring feet on said indicator unit arranged to bear against said top end wall of said cylinder and tension said ring on said hub.

11. In an incentive spirometer having an indicator unit and an airway unit, said airway unit comprising a vertical cylinder containing a loosely fitting piston having a predetermined rate of air leakage, said cylinder having a top end wall and an open bottom end, an inhalation tube connected to said top end wall, an upstanding grooved hub mounted in saidtop end wall for quick detachable mounting of said indicator unit on said top end wall, said hub having a vertical bore communicating with the interior of the cylinder to receive an actuating member on said indicator unit, and stop means in a lower side wall portion of said cylinder to retain said piston in the cylinder.

12. In an incentive spirometer having an indicator unit and an airway unit, said indicator unit comprising a housing having spring feet, a connector pin ring on the bottom of said housing, a counter and an indicator light in said housing, a switch for turning said light on and off, electrical power supply means for said indicator light, a rod guide column mounted for vertical movement in said housing to actuate said counter and switch, and a vertical volume indicating rod adjustably mounted in said rod guide column and projecting downward through said connector pin ring, said volume indicating rod being slidable in said connector pin ring. 

1. An incentive spirometer comprising an airway unit and an indicator unit; said airway unit comprising a vertical cylinder having a top end wall and an open bottom end, a loosely fitting piston in said cylinder having predetermined air leakage rate, and an inhalation tube connected with the upper end of said cylinder; said indicator unit comprising an electrical power supply means, a signal light, a switch in circuit with said light for turning said light on and off, and a switch actuating member for said switch; and quick detachable means connecting said two units together with said switch actuating member arranged to be lifted by upward movement of said piston to turn on said light when said piston has been raised to a predetermined position in said cylinder by inhalation of a person through said tube.
 2. A spirometer as defined in claim 1 including a counter in said indicator unit mounted for actuation by said switch actuating member.
 3. A spirometer as defined in claim 1 wherein said switch actuating member extends into said cylinder through said quick detachable connecting means.
 4. A spirometer as defined in claim 1, said quick detachable connecting means comprising complementary interengaging parts on said top end wall of said cylinder and the bottom of said indicator unit for mounting said indicator unit on said top end wall with said switch actuating member extending through an opening in said top end wall for engagement by said piston.
 5. A spirometer as defined in claim 1, said switch actuating member forming a stop to limit said upward movement of said piston.
 6. A spirometer as defined in claim 5, said switch actuating member comprising a rod mounted for engagement with said piston, a rod guide column mounted in said indicator unit and forming means having limited movement to actuate said switch, and means securing said rod in adjusted position in said rod guide column.
 7. An incentive spirometer comprising a vertical cylinder having a top end wall and an open lower end, an inhalation tube connected with the upper end of said cylinder, a loosely fitting piston in said cylinder having a predetermined air leakage rate, an indicator unit mounted on said top end wall of said cylinder and containing a counter and a signal light, a switch in said indicator unit for turning said light on and off, electrical power supply means for said signal light, a rod guide column mounted for vertical movement in said indicator unit and forming means to actuate said counter and switch, and a vertical volume indicating rod adjustably mounted in said rod guide column, the lower end of said rod extending into said cylinder for engagement by the top of said piston.
 8. A spirometer as defined in claim 7 including quick detachable means for connecting said indicator unit to said top end wall.
 9. A spirometer as defined in claim 8, said quick detachable means comprising a bayonet-type connector having a grooved hub on said top end wall of said cylinder and a ring on the bottom of said indicator unIt arranged to lock on said hub, said hub having a bore slidably receiving said rod.
 10. A spirometer as defined in claim 9 including spring feet on said indicator unit arranged to bear against said top end wall of said cylinder and tension said ring on said hub.
 11. In an incentive spirometer having an indicator unit and an airway unit, said airway unit comprising a vertical cylinder containing a loosely fitting piston having a predetermined rate of air leakage, said cylinder having a top end wall and an open bottom end, an inhalation tube connected to said top end wall, an upstanding grooved hub mounted in said top end wall for quick detachable mounting of said indicator unit on said top end wall, said hub having a vertical bore communicating with the interior of the cylinder to receive an actuating member on said indicator unit, and stop means in a lower side wall portion of said cylinder to retain said piston in the cylinder.
 12. In an incentive spirometer having an indicator unit and an airway unit, said indicator unit comprising a housing having spring feet, a connector pin ring on the bottom of said housing, a counter and an indicator light in said housing, a switch for turning said light on and off, electrical power supply means for said indicator light, a rod guide column mounted for vertical movement in said housing to actuate said counter and switch, and a vertical volume indicating rod adjustably mounted in said rod guide column and projecting downward through said connector pin ring, said volume indicating rod being slidable in said connector pin ring. 